CUHK in colon cancer test breakthrough

Top News | Carine Chow 29 Jul 2021

Testing bacterial DNA in feces can be more than 90 percent accurate in the detection of early stage colon cancer, a groundbreaking test developed by the Chinese University of Hong Kong found.

After 10 years on the project, researchers at the faculty of medicine developed the world's first fecal "bacterial DNA markers" test based on metagenomic analysis - direct genetic analysis of genomes contained with an environmental sample - on more than 1,100 cancer subjects.

The sensitivity of this noninvasive test, which they called "M3 CRC," is 94 percent for colorectal cancer detection, which is comparable to that of the colonoscopy, which is an invasive test.

Francis Chan Ka-leung, dean of medicine and the project's leading researcher, said the cost of the new test is less than that of a colonoscopy, but did not disclose the actual price. Chan added that the new test is also better than the fecal immunochemical test, a noninvasive test commonly used as a colorectal cancer screening tool.

"The fecal immunochemical test is very inaccurate in terms of detecting early cancers, with a sensitivity of less than 50 percent," he said.

Colorectal cancer is Hong Kong's most common cancer, accounting for about one sixth of all new cancer cases, statistics from the Hospital Authority in 2018 showed. It is also the second deadliest cancer, as 15.9 percent of cancer patients died of it in 2018.

But an early diagnosis may help, as the five-year survival rate of patients with stage 1 colorectal cancer is 96 percent, statistics from the Hong Kong Cancer Registry show.

The survival rate drops to less than 10 percent for stage 4 patients.

The cause of colon cancer usually stems from polyps, small clumps of cells that form on the lining of the colon.

Ng Siew-chien, associate director of the Centre for Gut Microbiota Research, said the team was thrilled about the discovery, as the novel test may make colon cancer prevention a reality by detecting polyps.

"Unlike blood tests or colonoscopic procedures that need clinic or hospital visits, this test only requires a small sample of stool and can be performed at home," she said. "The bacterial gene markers test can detect cancer early, when it can be cured."

She added that the test is simple and can potentially be applied globally.

Researchers say the test is already available, and those who are interested should consult their family practitioners regarding whether they should take the test.

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